works! awesome 
By default FDK-AAC cuts of anything above 17kHz when using CBR mode. It's possible to change it.
Vouk could you perhaps add button that changes this to 20kHz?
Workaround for this is to use ("VBR" In Voukoder) Quality Mode 5. Downside to this is that it has lower maximum bitrate.
Also discovered:
FDK-AAC on Voukoder uses wrong format profile according to mediainfo:
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LTP
Codec ID : mp4a-40-4
Duration : 3 min 29 s
Bit rate mode : Constant
Bit rate : 384 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 64.0 kHz
Frame rate : 62.500 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 9.61 MiB (81%)
Default : Yes
Alternate group : 1Sampling rate also seems to be wrong.
Sadly FDK still has that 'delay' at the beginning. I created a build myself with some tweaks to the header of output files, that reduced the delay by half, but still a delay remains nonetheless.
(attachment is nested as this is only for techies)
Sadly FDK still has that 'delay' at the beginning.
How much is this delay? Do you know if ffmpeg compiled with FDK has same issue?
Perhaps this delay could be avoided by bundling FDK with ffmpeg and using it that way.
Only for personal use of-course.
They have some wierd theory behind the delay and apparently it is intentional, even though FFMPEG's standard AAC doesn't do it, neither does Adobe's AAC or any other video-editing suite with AAC support for that matter.
It isn't an issue with FFMPEG, its by design inside FDK... the delay can be noticed in very highly sychronized fast action video by those who actually create the video... for example my better half says she can't tell the difference.
But where it really becomes apparent is when you re-import the mp4 with FDKAAC stream into Premiere and you will see the delay in the sample view.
Unless someone seriously into dissecting code was to fork FDKAAC and engineered their own changes in, I'm afraid it would be wise to just stick with alternative options, for now I just stick with raw 24 bit pcm and let the transcoding server deal with the distribution formats.
Edit:
Just want to add for newcomers to AAC... The standard AAC built into FFMPEG is actually BETTER than FDK-AAC at higher than 128kb bitrates. FDKAAC comes into its own below 128k and in part at 128k. But Nero is still the best IMO at all bitrates, but I don't think Vouk will ever add functionality to allow us to use the neroaacencode.exe binary?...
The standard AAC built into FFMPEG is actually BETTER than FDK-AAC at higher than 128kb bitrates. FDKAAC comes into its own below 128k and in part at 128k.
Do you have more info about this? In all my tests FFMPEGs AAC always sound worse in every bitrate.
Do you have more info about this? In all my tests FFMPEGs AAC always sound worse in every bitrate.
FDK-ACC sounds in my tests with 5.1 Channels at 384 Kbps (64 Kbps per Channel) better too.
Simple question, maybe. How can I check if libfdk-aac-2.dll is being picked up or not? I don't see an added option in the audio panel drop down. Using ProcessExplorer it's not attached to the PPro process as a library.
Is the use of libfdk-aac-2.dll still recommended for the 2.x versions of Voukoder, or is the quality of the native AAC encoder better now?
Thank you for response, I tried to find some more informations about it in the ffmpg wiki, but unfortunately it makes it not quite clear:
https://trac.ffmpeg.org/wiki/Encode/AAC
The Fraunhofer FDK AAC codec library. This is currently the highest-quality AAC encoder available with ffmpeg.
and then, later
For AAC-LC: as of 2017 this is no longer necessarily the case. The built in aac encoder is quite good.
Fo me it sounds like the built in acc encoder makes no difference in AAC-LC, but it still does in main profile. However, I think I have to do some tests of my own, and yes, you're right, lossless is the best but ...not so efficient.
I did some tests with a sequence of white noise. I made a screenshot of the spectralview in Audition. The results are attached as PNG-pictures:
01-uncompreessed.png: Uncompressed - this is what it shoul look like
02-AAC-ffmpg_CBR_320.png: The native FFMPG AAC Encoder at 320kbit (48Khz stereo) - look at these "glitches"
03-AAC-ffmpg_CBR_384.png: Same settings but slightly higher bitrate (384kbit) - noticeably better quality
04-fdkAAC_CBR_320.png: fdk AAC Encoder at 320kbit, very good quality, but frequencies above 17Khz are cut
05-AAC_x264Pro-plug-in: AAC Encoder of the x264Pro plug-in. I don't know what encoder is used here but it looks outstanding
So my result is: For best AAC quality in voukoder use the native FFMPG AAC encoder at higher bitrates (min 384) or use the the fdk encoder and live without the 17.000+ frequencies. After some rock concerts these frequencies are blows away, anyway 
)
Workaround for this is to use ("VBR" In Voukoder) Quality Mode 5. Downside to this is that it has lower maximum bitrate.
I just realized i did not include vbr=5 in the encoder config. I had options vbr=0 to vbr=4 instead of vbr=1 to vbr=5. Fixed that.
But i still recommend to use a lossless codec (if possible) if you really want outstanding audio.
Yes, but in some cases you need to have mp4 file so you have to use AAC audio. It would be nice if you added ability to use Apple CoreAudio AAC. I'm sure its possible to do since OBS does this too (when its installed on system).
